Why Airplane Food Tastes So Bad and Other Curious Phenomena

We found answers to 11 compelling questions about how the human body works.

Travis Rathbone for Reader’s Digest

How come the food I eat on airplanes is so bland?

“At 35,000 feet, the first thing that goes is your sense of taste,” explains Grant Mickels, executive chef for culinary development of Lufthansa’s LSG Sky Chefs. The quality of the food isn’t the issue. In a mock aircraft cabin, German researchers tried out ingredients at both sea level and in a pressurized condition at 8,000 feet. The tests revealed that the cabin atmosphere “makes your taste buds go numb, almost as if you had a cold,” says Mickels. Our perception of saltiness and sweetness drops by around 30 percent at high altitude. Decreased humidity in the cabin also dries out your nose and dulls the olfactory sensors essential for tasting flavors.—Barbara Peterson, from Condé Nast Traveler

Why do I hate the sound of my own voice on a recording?

Every sound we hear—birds chirping, bees buzzing—is a wave of pressure moving through the air, which our outer ears “catch” and funnel through the ear canal to be interpreted by the brain. When you speak, your ear is stimulated by internal vibrations from your vocal cords and by the sound coming out of your mouth and traveling through the air and into the ears. This combination gives your voice (as you hear it) a fuller, deeper quality that’s lacking when you hear it on a recording.—Matt Soniak, from Mental Floss

I always seem to wake up just a few minutes before my alarm clock goes off. Why is this?

In anticipation of the day, your body starts to churn out certain stress-related hormones during the later stages of sleep, says Jan Born, a professor of behavioral neuroscience at the University of Tübingen in Germany. His research team found that sleepers had more of the hormone adrenocorticotropin in their blood when they expected to be wakened at a certain time. Genes also play a role. One University of Kansas study pinpointed the gene KDM5A as the so-called alarm clock gene, which controls when our own personal “rise and shine” switch is flipped.—Sarah Klein, from huffingtonpost.com

How come bruises go through a range of colors before they fade?

A bruise occurs when small capillary blood vessels break under the skin. Hemoglobin in this leaked blood gives the bruise its classic purplish hue. The body then ropes in white blood cells to repair the damage, causing hemoglobin to break down into biliverdin, which is green, and then bilirubin, which is yellow. The debris at the bruise site ultimately clears, and the color fades.—From New Scientist

Does sweating guarantee that I’ve gotten a good workout?

A workout’s benefits derive from exercise itself, not how much you sweat. The more intense the effort, the greater the health benefits and, generally, the more you sweat (your body’s natural response to your core temperature rising). But perspiring, in and of itself, does not amplify those effects (not even calorie burning). You could sweat a lot due to a hot or humid environment, and you wouldn’t get any extra fitness benefit.—Gretchen Reynolds, from The New York Times

Why does food taste bad after I brush my teeth?

Thank sodium laureth sulfate for ruining your breakfast. This surfactant—added to toothpastes to create foam and make the paste easier to spread—suppresses receptors on our taste buds that perceive sweetness. It also breaks up the tongue’s phospholipids, enhancing bitter tastes. To end this torture, consider a toothpaste without this ingredient—or brush after meals instead of, say, right before breakfast.—Matt Soniak, from Mental Floss

I’ve read that surgeons can operate on a person’s brain without an anesthetic, since the brain has no pain receptors. So what is a headache?

The brain itself has no pain-sensing neurons. But the dura mater—the thick membrane surrounding the brain beneath the skull—is filled with pain receptors. Both it and the sensitive site of cranial incision on the skin get local anesthetic during surgery, says Dimitris Placantonakis, MD, a neurosurgeon at New York University. Headaches can occur when the dura or other non-brain structures, like muscles and sinuses, are irritated, inflamed, or under pressure. Whether the disturbance results from a tumor, trauma, or the freeze of triple-churned ice cream, pain-sensing receptors in the head send signals to the brain, which processes them as “ow!”—James Carlton, from Discover

Why are the blood vessels in our eyes more visible when we’re tired?

Sleepiness slows down blinking, which normally keeps the outer layer of the eye lubricated. Dryness triggers mild inflammation and dilation of blood vessels that are usually invisible. Blinking more frequently may help ease discomfort.—From New Scientist

Do hair and nails keep growing after you die?

Hair and nails stop growing pretty much as soon as a person kicks the bucket. But when someone dies, his skin dries out and pulls away from nails and hair, making them appear to grow. The growth of new cells requires oxygen and sugar, things that are no longer available to someone who has died.—Courtesy of Smithsonian Enterprises, smithsonian.com

Why do annoying songs get stuck in my head?

Because you’re unfamiliar with the lyrics. People can recall the first verse of a song, but after the chorus, they might stumble over the words. The song becomes incomplete, which transforms into an intrusive thought, according to Ira Hyman Jr. of Western Washington University. Songs intrude during tasks that are either difficult, causing the mind to wander, or easy, allowing repetitive thoughts to enter. To flush out these stuck songs, called earworms, find an engaging task that requires the auditory and verbal components of your working memory, like reading a good book or watching a favorite show.—Anahad O’Connor, from The New York Times

In TV shows or movies, characters often urge a wounded figure to stay with them, not to lose consciousness. Is there any medical basis for this?

No. If someone’s about to fall into a coma, there’s nothing you can say to stop it. Whatever problem is causing a loss of consciousness—stroke, drug overdose, or something else—will generally continue to unfold irrespective of a patient’s state of awareness. It’s often said that head-injury patients should be kept awake, on the theory that dozing off could send them into a coma. Many doctors say that’s not the case. The one thing they do watch for in an unresponsive patient is hindered breathing. ER doctors and technicians are trained to keep a victim’s airway clear. They may do this by inserting a tube into the trachea—not by begging her to stay alert.—Daniel Engber, from slate.com